The present invention generally relates to solid debris removal from a liquid stream. In particular, the present invention relates to an apparatus for intercepting debris and trash moved by a liquid through a conduit, pipe, channel, tank or well, and automatically elevating the removed trash and debris to a receptacle or conveying system.
Screening devices are commonly used for removing solid materials from liquid flow streams, such as in waste water treatment systems, food processing lines, and the like. Such devices typically include a screen that is disposed in the liquid flow stream for screening solids and debris from the flow stream, and a rake that is cyclically operated for removing the accumulated materials from the screen. With such screening devices, a lift often is employed for receiving and elevating the screened debris and solids to a suitable discharge height for dumping into a transfer conveyor, bin, truck or the like. Such lifts generally include a solids receiving container into which the solids are received from the screening device, and means for raising the container to the desired elevated location for dumping. Because movement of the lift container is dictated by the specific arrangement of the screening device and transfer conveyor or receiving bin, and often required multi-directional transfer, conventional lifts have been relatively complicated in construction and operation and require custom design for proper installation. Falling debris and other contaminating materials that can exist or accumulate on the equipment also can hinder proper operation, particularly when precision interaction is required between moving mechanical parts. Lifting of heavy, water-laden loads has presented further operating problems.
Prior art self-relieving bar screens with rakes have very complex mechanical drive systems such as cable and pulley systems, chain and sprocket systems, rack and pinion systems, or manual systems of similar design. Systems of the prior art are high maintenance and inefficient, allowing the accumulation of debris or the pass-through of debris and trash during the cleaning cycle. Due to their design, the prior art systems had many moving parts subject to wear and tear and requiring maintenance. Additionally, systems of the prior art typically have drive parts at or below the incoming water channel or conduit level which can become contaminated, corroded or jammed, or otherwise cause malfunction. Hence, existing lifts have been relatively expensive, and by virtue of their complexity and the environments in which they are used, subject to considerable maintenance.
The present invention is generally located in an unmanned environment where reliability is very important since trash buildup defeats the purpose of the invention.